Put the trans in neutral and rotate the driveshaft until the crosspin hole is facing you. Then grab a tire and rotate until the 2 spider gears are perfectly lined up with the hole. Then push out on the tires to get the c-clips bottomed out. Then try to push the carrier pin back in. If this is the same pin that just came out, rotate the carrier 180 degrees and try again. If you're certain everything is a-ok, get a deadblow mallet and "coerce" it back in medival style. Thats what I had to do with mine: the ring gear was so thick, it was rubbing the pin.